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	perf: Enhance perf to allow for guest statistic collection from host
Below patch introduces perf_guest_info_callbacks and related register/unregister functions. Add more PERF_RECORD_MISC_XXX bits meaning guest kernel and guest user space. Signed-off-by: Zhang Yanmin <yanmin_zhang@linux.intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
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					 4 changed files with 77 additions and 13 deletions
				
			
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			@ -135,17 +135,10 @@ extern void perf_events_lapic_init(void);
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 */
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#define PERF_EFLAGS_EXACT	(1UL << 3)
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#define perf_misc_flags(regs)				\
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({	int misc = 0;					\
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	if (user_mode(regs))				\
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		misc |= PERF_RECORD_MISC_USER;		\
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	else						\
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		misc |= PERF_RECORD_MISC_KERNEL;	\
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	if (regs->flags & PERF_EFLAGS_EXACT)		\
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		misc |= PERF_RECORD_MISC_EXACT;		\
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	misc; })
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#define perf_instruction_pointer(regs)	((regs)->ip)
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struct pt_regs;
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extern unsigned long perf_instruction_pointer(struct pt_regs *regs);
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extern unsigned long perf_misc_flags(struct pt_regs *regs);
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#define perf_misc_flags(regs)	perf_misc_flags(regs)
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#else
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static inline void init_hw_perf_events(void)		{ }
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			@ -1720,6 +1720,11 @@ struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
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{
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	struct perf_callchain_entry *entry;
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	if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
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		/* TODO: We don't support guest os callchain now */
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		return NULL;
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	}
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	if (in_nmi())
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		entry = &__get_cpu_var(pmc_nmi_entry);
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	else
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			@ -1743,3 +1748,29 @@ void perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int ski
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	regs->cs = __KERNEL_CS;
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	local_save_flags(regs->flags);
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}
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unsigned long perf_instruction_pointer(struct pt_regs *regs)
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{
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	unsigned long ip;
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	if (perf_guest_cbs && perf_guest_cbs->is_in_guest())
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		ip = perf_guest_cbs->get_guest_ip();
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	else
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		ip = instruction_pointer(regs);
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	return ip;
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}
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unsigned long perf_misc_flags(struct pt_regs *regs)
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{
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	int misc = 0;
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	if (perf_guest_cbs && perf_guest_cbs->is_in_guest()) {
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		misc |= perf_guest_cbs->is_user_mode() ?
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			PERF_RECORD_MISC_GUEST_USER :
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			PERF_RECORD_MISC_GUEST_KERNEL;
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	} else
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		misc |= user_mode(regs) ? PERF_RECORD_MISC_USER :
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			PERF_RECORD_MISC_KERNEL;
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	if (regs->flags & PERF_EFLAGS_EXACT)
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		misc |= PERF_RECORD_MISC_EXACT;
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	return misc;
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}
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			@ -288,11 +288,13 @@ struct perf_event_mmap_page {
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	__u64	data_tail;		/* user-space written tail */
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};
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#define PERF_RECORD_MISC_CPUMODE_MASK		(3 << 0)
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#define PERF_RECORD_MISC_CPUMODE_MASK		(7 << 0)
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#define PERF_RECORD_MISC_CPUMODE_UNKNOWN	(0 << 0)
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#define PERF_RECORD_MISC_KERNEL			(1 << 0)
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#define PERF_RECORD_MISC_USER			(2 << 0)
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#define PERF_RECORD_MISC_HYPERVISOR		(3 << 0)
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#define PERF_RECORD_MISC_GUEST_KERNEL		(4 << 0)
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#define PERF_RECORD_MISC_GUEST_USER		(5 << 0)
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#define PERF_RECORD_MISC_EXACT			(1 << 14)
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/*
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			@ -446,6 +448,12 @@ enum perf_callchain_context {
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# include <asm/perf_event.h>
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#endif
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struct perf_guest_info_callbacks {
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	int (*is_in_guest) (void);
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	int (*is_user_mode) (void);
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	unsigned long (*get_guest_ip) (void);
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};
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#ifdef CONFIG_HAVE_HW_BREAKPOINT
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#include <asm/hw_breakpoint.h>
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#endif
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			@ -932,6 +940,12 @@ static inline void perf_event_mmap(struct vm_area_struct *vma)
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		__perf_event_mmap(vma);
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}
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extern struct perf_guest_info_callbacks *perf_guest_cbs;
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extern int perf_register_guest_info_callbacks(
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		struct perf_guest_info_callbacks *);
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extern int perf_unregister_guest_info_callbacks(
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		struct perf_guest_info_callbacks *);
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extern void perf_event_comm(struct task_struct *tsk);
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extern void perf_event_fork(struct task_struct *tsk);
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			@ -1001,6 +1015,11 @@ perf_sw_event(u32 event_id, u64 nr, int nmi,
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static inline void
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perf_bp_event(struct perf_event *event, void *data)			{ }
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static inline int perf_register_guest_info_callbacks
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(struct perf_guest_info_callbacks *) {return 0; }
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static inline int perf_unregister_guest_info_callbacks
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(struct perf_guest_info_callbacks *) {return 0; }
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static inline void perf_event_mmap(struct vm_area_struct *vma)		{ }
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static inline void perf_event_comm(struct task_struct *tsk)		{ }
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static inline void perf_event_fork(struct task_struct *tsk)		{ }
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			@ -2797,6 +2797,27 @@ void perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip, int ski
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}
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/*
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 * We assume there is only KVM supporting the callbacks.
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 * Later on, we might change it to a list if there is
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 * another virtualization implementation supporting the callbacks.
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 */
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struct perf_guest_info_callbacks *perf_guest_cbs;
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int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
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{
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	perf_guest_cbs = cbs;
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	return 0;
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}
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EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
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int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
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{
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	perf_guest_cbs = NULL;
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	return 0;
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}
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EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
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/*
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 * Output
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 */
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			@ -3749,7 +3770,7 @@ void __perf_event_mmap(struct vm_area_struct *vma)
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		.event_id  = {
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			.header = {
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				.type = PERF_RECORD_MMAP,
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				.misc = 0,
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				.misc = PERF_RECORD_MISC_USER,
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				/* .size */
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			},
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			/* .pid */
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